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41.
以van Genuchten模型表述的土壤水分特征曲线为基础,推导出流域单点缺水量,并结合TOPMODEL模型中地形指数与地下水位关系,建立了反映地形和土壤特征共同影响的蓄水容量模型,通过统计方法从栅格尺度蓄水容量获得流域尺度蓄水容量曲线,取代传统新安江模型中率定的蓄水容量曲线。以淮河流域紫罗山子流域为例,分析地形特征与土壤类型对蓄水容量的影响;并与实测流量过程以及原新安江模型模拟的流量过程对比,表明模型能较好地模拟场次洪水过程。模型将蓄水容量曲线显式表述,减少了新安江模型参数,为无资料地区的水文模拟提供了分析方法。 相似文献
42.
北太平洋副热带环流变异及其对我国近海动力环境的影响 总被引:1,自引:0,他引:1
我国东部陆架海和南海是国防安全的重要门户;位处第二岛链以西的副热带北太平洋既是各国争夺的重要海区,又是我国从近海走向大洋的重要通道.围绕"北太平洋副热带环流变异如何通过黑潮与我国近海动力环境之间相互作用"这一国际前沿科学问题,国家重点基础研究发展计划项目"北太平洋副热带环流变异及其对我国近海动力环境的影响"于2007年9月正式立项.该项目不仅有助于拓展和丰富海洋动力学理论,揭示我国近海及邻近大洋动力环境变异机制,提高预测能力,而且也将为维护我国国防安全和海洋权益,为可持续开发利用海洋资源提供海洋动力环境保障.该项目主要研究内容包括:①北太平洋副热带环流变异和调整机理;②黑潮与我国近海的能量与水体交换过程及机制;③北太平洋副热带环流变异与大气驱动力的耦合效应;④我国近海及邻近大洋动力环境变异的可预测性研究.拟解决的关键科学问题为:北太平洋副热带内区环流变异的机理及其对黑潮的影响;黑潮源头变异机理及其对吕宋海峡水交换的影响和黑潮变异机理及其对东部陆架海域动力环境的影响. 相似文献
43.
20世纪70年代以来,北京地区陆续开展的地质灾害防治工作为首都防灾减灾提供了重要保障,如何满足新时代地质灾害防治的新要求,成为当前地灾防治面临的首要任务.回顾40年来北京地质灾害调查评价、监测、预警与防治工作,分析了当前极端气候条件下人类对地质灾害隐蔽性规律认识不清,人类工程活动引发地质灾害等环境地质问题,以及地质灾害防治工作与新时代具体要求的差距,结合北京具体情况,提出了"十四五"时期北京地质灾害综合防控工作思路,包括强化地质灾害调查评价体系、完善地质灾害监测预警体系、巩固综合治理体系、建强应急防治体系和深化科技创新体系5个方面. 相似文献
44.
Developing ecotourism in First World, resource-dependent areas 总被引:1,自引:0,他引:1
Deborah Che 《Geoforum》2006,37(2):212-226
Ecotourism, an economic diversification tool most commonly applied in the Third World as a means to protect ecosystems, preserve local cultures, and spur economic development, has recently been applied in First World resource-dependent areas. While ecotourism has traditionally focused on Third World ‘undisturbed’ protected lands, it has also been developed in their First World equivalents (i.e., old-growth forests) as well as in First World sites of past resource extraction and in places where current agricultural practices maintain cherished cultural landscapes. Forest County, Pennsylvania, a timber-dependent area, sought to diversify its economy by developing ecotourism based on its unique Allegheny hardwood forests, which are produced by timber harvesting. This ecotourism would encourage amenity-based, locally-driven economic development and maintain timber harvesting. While government and foundation supported ecotourism development efforts in areas dependent on resource extraction have incorporated some of ecotourism’s ideals, these operations have had mixed success. Such isolated areas, which have traditionally drawn visitors independently engaging in traditional outdoor recreation activities, have not been able to draw enough customers willing to pay for natural and cultural history tours. If ecotourism is to be successful, such areas may need further government support and destination branding to increase name recognition in order to counter the global orientation of the nature tour industry. For true community development, local collaborative efforts including resource and environmental interests are also required in which primary production is connected to processing and consumers through value-added and service sector activities such as tourism. 相似文献
45.
46.
WANG Jinrong HU Yongbin HUANG Shufeng CHEN Bin YE Yuansheng LUO Xiaohua Lv Xinbiao 《《地质学报》英文版》2017,91(Z1):289-290
<正>1 Introduction Rare-metal granites are widely distributed in South China.The Daping porphyritic granitic Ta-Nb deposit,located in the Yongding area of south Fujian province,South China,is a large rare-metal deposit recently discovered.Few studies have been made of its petrology,mineralogy,geochemistry,chronology and metallogeny.In recent years,several exploratory drillings have been done in this deposit.These drilling holes,from 380 to 600 相似文献
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48.
Dynamic land use change simulation using cellular automata with spatially nonstationary transition rules 总被引:2,自引:0,他引:2
The dynamic relationships between land use change and its driving forces vary spatially and can be identified by geographically weighted regression (GWR). We present a novel cellular automata (GWR-CA) model that incorporates GWR-derived spatially varying relationships to simulate land use change. Our GWR-CA model is characterized by spatially nonstationary transition rules that fully address local interactions in land use change. More importantly, each driving factor in our GWR model contains effects that both promote and resist land use change. We applied GWR-CA to simulate rapid land use change in Suzhou City on the Yangtze River Delta from 2000 to 2015. The GWR coefficients were visualized to highlight their spatial patterns and local variation, which are closely associated with their effects on land use change. The transition rules indicate low land conversion potential in the city’s center and outer suburbs, but higher land conversion potential in the inner near suburbs along the belt expressway. Residual statistics show that GWR fits the input data better than logistic regression (LR). Compared with an LR-based CA model, GWR-CA improves overall accuracy by 4.1% and captures 5.5% more urban growth, suggesting that GWR-CA may be superior in modeling land use change. Our results demonstrate that the GWR-CA model is effective in capturing spatially varying land transition rules to produce more realistic results, and is suitable for simulating land use change and urban expansion in rapidly urbanizing regions. 相似文献
49.
Keh‐Chyuan Tsai Chung‐Che Chou Chi‐Lon Lin Pei‐Ching Chen Sheng‐Jhih Jhang 《地震工程与结构动力学》2008,37(4):627-645
This paper first presents the force–deformation relationship of a post‐tensioned (PT) steel beam‐to‐column connection constructed with bolted web friction devices (FDs). This paper then describes the test program conducted in the National Center for Research on Earthquake Engineering, Taiwan, on four bolted FDs and four full‐scale PT beam‐to‐column moment connection subassemblies using the FDs. Tests confirm that (1) the hysteretic behavior of four bolted FDs is very stable, (2) the friction coefficient between the steel plate and the brass shim is about 0.34, (3) the proposed force–deformation relationships reasonably predict the experimental responses of the PT connections under cyclically increasing deformations up to a beam peak rotation of 0.05 rad, and (4) the decompression moments do not degrade as beam cyclic deformations increase. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
50.
本研究以物联网技术为基础,利用条码、二维码和射频电子标签标识、射频扫码技术、声光电自动感应技术、GPS/GIS技术进行信息采集,建立人工影响天气装备弹药物联网管理系统,实现人工影响天气装备弹药从生产、验收、转运、仓储到发射作业的全程监控。在北京、陕西、贵州、河南4个地区进行试点开发研究,根据有源/无源射频识别(RFID)、二维码/条形码、火箭弹/高炮炮弹以及信息采集技术分别开展不同技术模式的应用试验,将弹药信息按照统一格式汇集至国家级物联网系统,有效提高了全国人工影响天气装备弹药信息采集的准确性和时效性,并结合有效传感器、无线通信技术,解决了大范围内的作业数据自动化采集及地面作业信息实时监控,提高人工影响天气作业安全管理的科技水平和业务信息化现代化程度,对全国开展人工影响天气装备物联网建设工作具有较强的参考价值。 相似文献